WASHINGTON, Sept. 4 (UPI) -- A consumer group Wednesday called for the federal government to halt a study examining whether common pain-killing drugs can prevent Alzheimer's disease because the group says the drugs used in the study have been shown to be ineffective.
Public Citizen also charged, in a letter to Health and Human Services Secretary Tommy Thompson, that people enrolled in the study are being exposed to potentially serious side effects from the drugs, which include Naprosyn and Celebrex, painkillers commonly used to treat arthritis.
"The study should be immediately stopped," Sid Wolfe, director of Public Citizen's Health Research Group, told United Press International.
Wolfe noted people in the study would be taking Celebrex for 7 years, and over this amount of time the risks due to the drug "start mounting." These risks include liver toxicity that can lead to death, kidney toxicity, gastrointestinal damage and infringement of bone healing.
Patients in the study, funded by the National Institutes of Health, are not being informed fully of the potential for these side effects or the alleged ineffectiveness of the drugs to prevent Alzheimer's, the degenerative brain illness that affects as many as four million Americans, Wolfe said.
The NIH began the 7-year study last year to look at whether a class of painkillers known as non-steroidal anti-inflammatory drugs, or NSAIDs -- including Naprosyn, ibuprofen and Celebrex -- could prevent Alzheimer's. The study was slated to enroll more than 2,600 people over age 70. So far, 1,000 people have enrolled at six centers across the United States.
The study was based on observational evidence suggesting that people who took these drugs regularly had a lowered risk of developing Alzheimer's.
However, Public Citizen claims in the letter recent studies that became available after the study began have shown only certain NSAIDs -- not Naprosyn and Celebrex -- have the potential to prevent Alzheimer's.
Alzheimer's experts, however, discounted Public Citizen's claims. Paul Aisen, director of the memory disorders program at Georgetown University in Washington, was involved in a study Public Citizen cited in its letter supporting its argument that the drugs will not prevent Alzheimer's.
Aisen's study, which was presented in July at an Alzheimer's disease conference in Stockholm, found Naprosyn and Vioxx -- a drug similar to Celebrex -- to be ineffective for halting the progression of Alzheimer's in patients who already had symptoms of the disease.
"Our study does not mean that the NIH prevention trial will not be successful," Aisen told UPI, noting his study involved people who already had Alzheimer's.
"The NIH study should not be stopped based on the results of our trial," he said. Naproxen and Celebrex "certainly may have a preventative effect, and if the trial is stopped prematurely, we may never know," Aisen added.
Vicky Cahan, spokeswoman for the National Institute of Aging -- the NIH agency overseeing the study -- told UPI, "NIA is reviewing the letter." She added the study is still ongoing at this point.
Bill Pierce, spokesman for the HHS, which oversees the NIH and to which Public Citizen addressed the letter, told UPI, "The most important thing is this is just one organization's opinion."
In response to claims that people enrolled in the trial were not informed of the risks, John Breitner, a psychiatrist at the University of Washington School of Medicine in Seattle who is the principal investigator of the study, said in a written statement, "Patients who receive the test medications ... were adequately informed in the consent form they signed upon entering the trial regarding the potential risks of the study medicines."
Public Citizen's letter claimed recent research has shown only NSAIDs that block an enzyme called secretase have the potential to prevent Alzheimer's. The group noted Naprosyn and Celebrex do not block this enzyme.
Aisen pointed out, however, the secretase research was done in animals and thus might not hold true in humans. "I do not view that as a reason that the NIH trial should be stopped," he said.
Breitner agreed with Aisen and noted, "The effort to prevent Alzheimer's disease requires investigation into all the avenues that show promise, and NSAIDs may well play a strong preventive role."
Aisen added that he "remains interested in the idea that NSAIDs may be useful for preventing Alzheimer's." His group is "still considering testing other anti-inflammatory drugs" to determine if they have a beneficial effect on the disease.
